When did Goku turn into a ss2?

Answer 1

When he and Gohan were in the time chamber training to take on Cell at his tournament. Goku hit ss2 but realized it had a major flaws due to the large build so he and Gohan worked on increasing their power without having to change their form. That is also the reason when they came out of the chamber they were still in their ss forms which they stayed they way till Cell was defeated.

this is not true goku did not go ss2 in the hyperbolic time chamber because like trunks and vegeta he only went super super saiyan which is like super saiyan 1.5 the bulky form however he did go ss2 when he fought majin vegeta he goes ss2 and there is always lightning and ss2 is very fast as proved by gohan when he killed all the cell juniors.

wrong

goku turn ssj2 in buu sega during the fight with vegeta the ss2 he is speeking of is the 1 what trunks achive its boltti muscle form its like half ssj2